Extending a ring circuit, metal conduit system

[javajock]

Hi there,
I wish to extend a ring main by adding three new sockets. The exsisting socket is a metal conduit system. 2 lives and neutals in box with earth wire from socket back to box. Is it exceptable to use this box as a junction. Running pvc sheathed cables to new sockets and back to original box again. Can the earth wires be connected to the original metal conduit box.
Scott

 

[securespark]

Not being funny, but did you have any other ideas of how to go about it?

 

[plugwash]

having never worked with steel conduit its always puzzled me how its extended/modified, do you get special tees/couplers with a reversed thread so you can insert them in an existing run or what?

 

[Pensdown]

You make a thread called a runner which is twice as long as normal. You screw on a locknut/ring first and then a coupler. You butt this to another piece of conduit with a normal thread and run the coupler off the runner onto to the normal thread and tighten it up. The locknut is then used to tighten up against the back of the coupler. You can also put a nipple into a thru/T box, the principal is the same

 

[Steve]

You make a thread called a runner which is twice as long as normal. You screw on a locknut/ring first and then a coupler. You butt this to another piece of conduit with a normal thread and run the coupler off the runner onto to the normal thread and tighten it up. The locknut is then used to tighten up against the back of the coupler. You can also put a nipple into a thru/T box, the principal is the same

T+E it is then . . . .



But surely, where the conduit is not nessecary for protecting the cable, why extend the conduit when extending the cable? Just knock out a blank on the box you are extending from, and run T+E through a gland. I expect this would be acceptable.

 

[Pensdown]

T+E it is then . . . .



But surely, where the conduit is not nessecary for protecting the cable, why extend the conduit when extending the cable? Just knock out a blank on the box you are extending from, and run T+E through a gland. I expect this would be acceptable.

Very acceptable and simple, I was just answering the question from Plugwash about joining conduit.

Just for information, the other way to break into a conduit system is to use a skeleton box which is a besa box with no back. It's mounted on top of another besa box which allows you to get into a conduit system without any cutting.

 

[plugwash]

Just for information, the other way to break into a conduit system is to use a skeleton box which is a besa box with no back. It's mounted on top of another besa box which allows you to get into a conduit system without any cutting.

looks bloody awfull though

 

[securespark]

Not when the box is in the floor void....

 

[plugwash]

alright i suppose if its hidden, but i've seen it done exposed.........

 

[Lectrician]

If the original install was done in steel, I would want to extend in steel. I hate seeing T+E bodged into other wiring systems.

Where is the install? Shop, factory, house??

 

[Steve]

OOI, on a suspended concrete floor (1st floor), with buried metal conduits, how deep do they have to be? Is there a requirement? I have worked in a shop with a conduit system, and in places on the upstairs concrete warehouse floor, you can see the metal conduit showing through the concrete.

 

[Lectrician]

Thats just it - It's steel conduit.........and hopefully earthed

If you where to damage the wiring the system, you would cause the fuse to blow before causing any danger........but lets face it - steel conduit is *fairly* hard to damage.

I have worked in places where we have installed the conduit in floor screeds, but in block and beam floors with fewer floor points, the norm is to run the conduit/wiring system below and pop up through the floor - especiall if the ceiling below is a suspended type!